Integration of high volume (high penetration) of photovoltaic (PV) generation with power grids consequently leads to some technical challenges that are mainly due to the intermittent nature of solar energy, the volume of data involved in the smart grid architecture, and the impact power electronic-based smart inverters. These challenges include reverse power flow, voltage fluctuations, power quality issues, dynamic stability, big data challenges and others. This paper investigates the existing challenges with the current level of PV penetration and looks into the challenges with high PV penetration in future scenarios such as smart cities, transactive energy, proliferation of plug-in hybrid electric vehicles (PHEVs), possible eclipse events, big data issues and environmental impacts. Within the context of these future scenarios, this paper reviewed the existing solutions and provides insights to new and future solutions that could be explored to ultimately address these issues and improve the smart grid’s security, reliability and resiliency.

The power transfer efficiency and performance of solid-state transformers (SST) highly depends on the design of its High-frequency transformers (HFTs) which is required to provide galvanic isolation between the primary and secondary side converters. Therefore, to achieve a highly efficient SST regardless of its topology, the design optimization of the HFTs becomes imperative. Also, high power density of SSTs are desirable which largely depends on the power density of the HFT. In this paper, a multi-physics-based design and multi-objective optimization of HFTs for SST applications is proposed. The proposed algorithm (based on time-harmonic electromagnetic, thermal and fluid physics model coupling) minimizes the volume of the HFT (consequently maximizes its power density), total cost as well maximizes its efficiency (by minimizing its total power loss). A case study of 20kW, 10 kHz investigated and its Pareto solutions presented. The simulation results show the various dependencies of the design variables on the proposed objectives function which verifies effectiveness of the proposed algorithm. The Pareto-optimal solutions show that efficiencies above 99\% can be achieved with appropriate selection of the design variables. From the Pareto solutions, two case studies of the HFTs (referred to as HFT1 and HFT2 using AMCC-100 and AMCC-250 amorphous cores respectively) are further investigated based on multi-physics numerical models and presented. An experimental implementation of the optimized HFTs (HFT1 and HFT2) and a self-tuned dual active bridge converter are carried out to validate the performance of the HFT based on the optimized simulation parameters. The experimental measurements from the HFTs are in very good agreement with the optimization results.

This paper proposes an algorithmic formulation for optimal PV hosting and placement of distributed energy resources (DER) for network resiliency enhancement. The algorithm incorporates a unique critical infrastructure (CI) ranking scheme to prioritize the CI nodes for the DER placement while ensuring maximum hosting of the DER. The proposed multi-objective non linear programming formulation is validated on an IEEE 34 bus feeder with different outage scenarios caused by a hurricane event. The simulation has produced 18 Pareto Optimal Solutions showing several options of optimally locating the DERs in order to achieve a maximum DER hosting capacity, improve system’s resiliency and minimize the system’s active power loss while satisfying all network and power flow constraints. The results verify the effectiveness of the proposed algorithmic formulation which distribution planners and designers can apply directly to multitude of their network substations to improve the overall system’s resiliency through grid-scale situation awareness.

Dynamic wireless charging systems (DWCS) for electric vehicles is an effective solution to overcome driving range anxiety, high volume, and cost of battery by offering continuous charging for electric vehicles in motion. However, this technology suffers from some challenges associated with the high cost of infrastructure and power pulsation at the battery side, hindering the widescale commercial adoption of the technology. As the electric vehicle moves along the transmitter coils, power pulsation arises due to fluctuation in the mutual coupling, which deteriorates the battery’s lifetime and the overall system’s efficiency. In recent years, a significant volume of research methodologies have been proposed to address power fluctuation in DWCS. These methods can be categorized into three main areas, which include developing magnetic coil structures to suppress the coupling variation, optimizing the compensation network for coping with the coupling fluctuation, and applying controllers for output power stabilization. This paper presents a comprehensive review of the current literature on magnetic coil structures, compensation network topologies, and control schemes aiming to address the impacts of power variation in DWCS. This paper gives a new and holistic insight into the challenges and the corresponding solutions to address the power pulsation issues in DWCS.

The interest for solar Photovoltaic (PV) systems installation has been recently increasing due to their reducing cost and high electricity price from the utilities. However, the PV power generation is sensitive to variable solar irradiation, which causes technical difficulties related to power quality and control. Severity of those problems directly depends on PV penetration level, grid design and geographic location. This paper explores the flicker indices of grid-tied PV power plant, one of the major power quality issues. The study has been carried out on a real grid-integrated PV system, situated at Engineering Center, Florida International University (FIU). The field measurements of various solar output power and flicker quantifying indices at the point of common coupling (PCC) have been recorded using data acquisition system and power quality meter respectively. The collected data has been categorized and analyzed for voltage fluctuations and flicker. Different approaches have been done to investigate the influence of PV power plant on the flicker indices. Results show that solar output power has a marginal effect towards flicker indices with existing penetration level. Load connection and variation are the key indicators of high flicker value during observation time.

A method of modulating the power level of a grid-supplied inductive Electric Vehicle (EV) charger to provide frequency stabilization to the utility grid is presented. The proposed controller can allow inductive EV charging systems to effectively respond to grid frequency fluctuations by online regulating the charging level and adding high virtual inertia. A new IPT multi-power level controller using simplified digital circuits is designed. The virtual inertia control/controller (VIC) is incorporated into the proposed multi-power level controller which gets the grid frequency measurement and online adjust the IPT’s charging level. Using the proposed VIC IPT charger, the switching cycles, as a result, the power transfer from the grid to the EV can be regulated in response to the grid frequency change. The simulation results of the proposed VIC IPT power controller are presented to show its effectiveness in response to power grid fluctuations. The proposed virtual inertia based controller is experimentally implemented and verified on an IPT setup connected to an actual small-scale Labvolt testbed.